Bromodomain (BRD)-containing proteins are essential for the recognition of acetylated lysine (KAc) residues of histones during transcriptional activation (Sanchez et al., The role of human bromodomains in chromatin biology and gene transcription. Current opinion in drug discovery & development 2009, 12, 659-65). BRDs have emerged as promising drug targets for a number of disease pathways that are characterized by changes in the epigenetic cell signature (Id.; Filippakopoulos et al., Selective inhibition of BET bromodomains. Nature 2010, 468, 1067-731). To date, only a few structurally diverse BRD inhibitors have been reported, all of which specifically target the KAc recognition sites of the bromodomain and extra terminal (BET) family of proteins (BRD2, BRD3, BRD4, and BRDT), each containing two tandem BRDs (Hewings et al., Progress in the development and application of small molecule inhibitors of bromodomain-acetyl-lysine interactions. J Med Chem 2012, 55, 9393-413; Muller et al., Bromodomains as therapeutic targets. Expert Rev Mol Med 2011, 13, e29; Prinjha et al., Place your BETs: the therapeutic potential of bromodomains. Trends Pharmacol Sci 2012, 33, 146-53). BET-inhibitors exert a broad spectrum of desirable biological effects such as anticancer and anti-inflammatory properties (Delmore et al., BET bromodomain inhibition as a therapeutic strategy to target c-Myc. Cell 2011, 146, 904-17; Matzuk et al., Small-Molecule Inhibition of BRDT for Male Contraception. Cell 2012, 150, 673-684; Mertz et al., Targeting MYC dependence in cancer by inhibiting BET bromodomains. Proc Nat Acad Sci USA 2011, 108, 16669-74; Ott et al., BET bromodomain inhibition targets both c-Myc and IL7R in high-risk acute lymphoblastic leukemia. Blood 2012, 120, 2843-52; Puissant et al., Targeting MYCN in neuroblastoma by BET bromodomain inhibition. Cancer Discov 2013, 3, 308-23). Of these, I-BET-762 (GSK525762) has recently entered clinical trials for the treatment of NUT midline carcinoma (Mirguet et al., Discovery of epigenetic regulator I-BET762: lead optimization to afford a clinical candidate inhibitor of the BET bromodomains. J Med Chem 2013, 56, 7501-15). Intense efforts are currently underway to discover new chemical scaffolds for hit-to-lead development campaigns of BET inhibitors as novel therapeutics (Filippakopoulos et al., Benzodiazepines and benzotriazepines as protein interaction inhibitors targeting bromodomains of the BET family. Bioorg Med Chem 2012, 20, 1878-86; Fish et al., Identification of a chemical probe for bromo and extra C-terminal bromodomain inhibition through optimization of a fragment-derived hit. J Med Chem 2012, 55, 9831-7; Mirguet et al., Naphthyridines as Novel BET Family Bromodomain Inhibitors. Chem Med Chem 2014, 9, 580-9; Seal et al., Identification of a novel series of BET family bromodomain inhibitors: binding mode and profile of I-BET151 (GSK1210151A). Bioorg & Med Chem Lett 2012, 22, 2968-72). Recently, BETs were discovered that interact with diverse kinase inhibitors (Martin et al., Cyclin-dependent kinase inhibitor dinaciclib interacts with the acetyl-lysine recognition site of bromodomains. Chem Biol 2013, 8, 2360; Ember et al., The acetyl-lysine binding site of bromodomain-containing protein 4 (BRD4) interacts with diverse kinase inhibitors. Chem Biol 2014; Ciceri et al., Dual kinase-bromodomain inhibitors for rationally designed polypharmacology. Nat Chem Biol 2014). Among these, the PLK1 inhibitor BI2536 and the JAK2/FLT3 inhibitors TG101348 and TG101209 inhibited the binding of KAc peptide to BRD4 with IC50 values of 0.03 and 0.13 μM, respectively, and showed strong downregulation of c-Myc in MM.1S cells. These activities were similar to that of the prototypic BET inhibitor JQ1, the most potent BRD4 inhibitor described to date. Furthermore, TG101348, but not JAK2 inhibitors that lack BET and FLT3 activity, potently inhibited proliferation of MV4-11 AML cells (IC50=79 nM)(Id.). AML is often driven by BETs and mutant FLT38 (Smith et al., Validation of ITD mutations in FLT3 as a therapeutic target in human acute myeloid leukaemia. Nature 2012, 485, 260-3) and the findings by Knapp and colleagues provided compelling evidence of an oncology indication that could be exploited through dual targeting of kinases and bromodomains. What are thus needed are new BRD inhibitors, for example, those with dual targeting activity, and uses of such inhibitors to treat various cancers. The compositions and methods disclosed herein address these and other needs.